As the feature sizes of microelectronic devices shrink, cooling issues become increasingly important. This is compounded by the fact that most devices are operating at ever-increasing speeds, and thus produce heat at an even greater rate than prior generations. Thus, modern devices produce more heat in smaller spaces that ever before.
Unfortunately, as the heat builds up within a microelectronic device, it tends to change the physical properties of the device. This tends to change the electrical characteristics of the device, often making it at least unreliable for its intended purpose, and in many instances, rendering the device wholly nonfunctional. Thus, there is a constant and growing need for means and methods by which heat can be removed from microelectronic devices.
Maintaining an ideal operating temperature for microelectronic devices is commonly achieved with heat sinks and air movement, which regulate temperature through a combination of thermal conduction and forced convection. This approach often requires additional components, such as a cooling fan that increases system size, weight and power requirements.
Alternate cooling techniques, such as low temperature co-fired ceramic structures, electrowetting-on-dielectric, liquid film cooling, variable thermal resistors, microjects, microchannel coolers, and thermoacoustic-based cooling have been employed, but none are universally applicable.
Additional impediments to cooling of microelectronic devices using some of these techniques are often imposed because of device packaging and encapsulation. Most of the techniques do not address localized hotspots within microelectronic devices or selective cooling of specific components therein without requiring active control or forced convection.
What is needed, therefore, is a cooling system that tends to reduce issues such as those described above, at least in part.